Theoretical Considerations on Electronic Properties of Cations of Melamine and Methylolmelamine, and a Relationship between the Band Maximum Wavelength of Ultraviolet Absorption Spectrum of Cation of Methylolmelamine and the Number of Methylol Group by the Molecular Orbital Method. (1) Cation of Melamine

Abstract

The total energies of the two-mono-cation models of melamine and the four di-cation models were calculated to determine the most stable model for each group by the CNDO/2 method.
On the other hand, the transition energies, wavelengths, and oscillator strengths of the mono-and di-cation models of melamine were calculated to obtain the simulation diagrams of their UV spectra. They were compared with the observed UV spectra of melamine in hydrochloric aqueous-solution.
From the energetic considerations on stability of the mono-and di-cation models and a comparison of the simulation diagram of UV spectrum of these cation models with the observed UV spectrum of melamine in hydrochloric aqueous solution, it was concluded that the cation of melamine in acidic aqueous solution may be almost mono-cation which a proton attached to the ring nitrogen atom of melamine.